Renewable fuse



W. 0. SMITH AND J. E. GRENACHE.

RENEWABLE FUSE.

APPLICATION nus!) SPT.7.19IB.

1,407,706. muted Feb. 28, 1922.

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RENEWABLE FUSE.

APPHCATION FILED SEPT. T. l9l8. 1,407,706.

Patented Feb. 28, 1922.

2 5HEEI'SSHEET 2.

Jfl 7 J3 JA j 6 7 AZ 7 UNITED STATES PATENT OFFICE.

WALTER 0. SMITH AND JOSEPH E. GRENACHE, OF NEW BEDFORD, MASSACHUSETTS,ASSIGNOBS '10 BEE-NU-IT ELECTRIC uauurac'ronmo COMPANY, OF NEW BED-FOBD, MASSACHUSETTS.

RENEWABLE FUSE.

Specification of Letters Patent.

Patented Feb. 28, 1922.

Application filed September 7, 1918. Serial No. 258,074,

To all whom it may concern Be it known that we, WALTER 0. SMITH andJosnrn E. (insxacns, citizens of the United States, residing at NewBedford, in the county of Bristol and State of Massachusetts, haveinvented certain new and use ful Improvements in Renewable Fuses, ofwhich the following is a specification.

This invention relates to an improved. renewable fuse and has as itsprimar object to provide a construction wherein rm and effectualelectrical connections willbe provided and maintained to thus overcomethe defects of inefficient contacts for the fuse link with attendantheating of the fuse.

The invention has as a further object to provide a construction whereindirect electrical connection will be formed between the terminals of thefuse link and the ferrules of the fuse and wherein the said terminalswill be wedged in engagement with the ferrules and thus firmly held tomake elec-- trical connection therewith.

A still further object of the invention is to provide a fuse employingsuitable wedge members for bindin the terminals of the fuse link inelectrica contact with the ferrules of the fuse and wherein-said wedgemembers may be adjustably shifted and rigidly held in en gement with theterminals fo'rthus estab ishing and maintaining a rigid contact betweenthe terminals and the fuse ferrules.

The invention has as a further object to provide a fuse wherein thegases created by the blowing of the fuse link will be permitted toreadil escape from the fuse.

And a still urther object is to provide a fuse which will becharacterized by simplicity and inexpensiveness of construction, whichmay be readil used in lieu of the ordinary fuse of simi ar type and willthus be adapted to eliminate a greater portion'of the usual expense forfuse maintenance, and wherein the fuse link may be readily insertedwithin the fuse and properl connected with the ferrules thereof.

ther and incidental objects will appear during the course of thedetailed'description of the invention. In the drawings, wherein we haveillustrated the preferred embodiment of the invention, and whereinsimilar reference characters designate correspondingrparts throughoutthe several views:

lgure 1' is vertical sectional view show F p'ositely ing our improvedfuse, this view being on an enlarged scale in order to clearly bring outthe structural details of the fuse,

Figure 2 is an enlarged elevation illustrating one end of the fusebroken away and shown in section at right angles to the plane ofthe-section of Figure 1,

*Figure 3 is a detail perspective view showing one of the wedge membersemployed,

Figure 4 is a -fragmentary sectional view showing the manner in whichthe fuse link is inserted in the fuse.

Figure 5. is a perspective view showing a slightly modified form oflink,

Figure 6 is a view similar to Figure 5 and showing a further modifiedform of link,

Figure 7 is a vertical sectional view showifrlllg, on an enlarged scale,a modified form of se Figure 8 is an end view of the fuse,

Fi re 9 is a' perspective view illustrating the errule lug employed 'inconnection with the mo ified form of fuse. and

Fi are 10 is a perspective view showing the use link employed inconnection with the modified form of fuse.

In carr ing the invention into effect we employ aharrel or receptacle10. This barrel may be formed of fiber or other suitable insulatingmaterial and preferably threaded upon the ends of the barrel are annularferrules 11 held against displacement by suitable locking pins 12. Theferrules are preferably constructed of copper or brass.

ormed in each of said ferrules substantially midway of its length is apair of opdisposed chordal shoulders 13 and, as will be observed uponreference to Figure' 1 of the drawings, the ends of the barrel abutthese shoulders for limiting the ferrules in their inward movement uponthe barrel when threaded thereon. Between each pair of shoulders isdefined an intermediate slot 14 and, as also shown in Fig- 1, theseslots are disposed in register. The slots are formed with flat parallelside walls providing contact surfaces 15 and the shoulders 13 are alsoformed with flat outer face! providing contact surfam 16 at OPPOSll'Isides of the slots.

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end of the fuse link is a pair of terminals 19. These terminals arepreferably formed of copper and. at their outer ends, the terminals ofeach pair are bent to provide oppositely directed lateral lugs 20. Aswill be noted, allof these lugs occupe' a common plane and are of alength to we freely received through the slots 14- of the ferrules l1.Consequently, the lugs at one. end of the fuse link may be insertedthrough the slot ofieither of the ferrules in the manner suggested inFigure 4 of the drawings. and the link then shifted longitudinallythrough the barrel '1". when said pair of lugs may then be insertedthrough the. slot of the other of the ferrules. In this position, the Ilink is then given a half turn to dispose the pairs of lugs in posltionengaging over the shoulders 13 of the ferrules fitting against ther-(intact surfaces 16 of said shoulders. The terminals 19 of each pairare spaced apart a distance corresponding to the width of each of theslots 14; Consequently. the shanks of these terminals will. when thelugs 20 are moved into position engaging over the shoulders. engage theside walls of the slots, fitting against the contact surfaces 15. Aswill be seen. the fuse link may be readily inserted within the fuse witha minimum of ditliculty so that when the link becomes blown. a new linkmay be casilv substituted therefor.

Removably fitted within the outer ends of the ferrulesare wedge members.each ,in-

cluding an annular head plate or disc 21 of a diametersomewhat lessthan-that of each of the ferrules. and formed on one side of said plateor otherwiseconnected thereto. is a diametric wedge block 22. The wedgeblocks are received within thc slots 14 of the ferrules between theterminals of the fuse link while the head plates 21 overlie theshoulders 13, of the ,ferrulcs. Removal'ily' threaded within the outerends of the ferrules to engage the head plates '21 of the wedge members.are followers in the form of closure plugs 23; Upon their inner sides.these plugs are provided with diamet'ric grooves 24 which communicatewith central passages 25 formed-axially through them. l'pon their outersides they are formed with.nicks or openings 26 in which a screw driveror other suitable tool may he engaged for adjusting the followers withinthe ferrules.

.\s will now be readily understood. the threaded followers or plugs 23may be screwed into the ferrules for shifting the wedge members inwardlywithout rotating them. and consequently forcing the blocks 2:! ofthcfwcdgc members into the slots 14 where the blocks will act to tightlybind the shanks of the link terminals against the contact surfaces 15.while the head plates '21 of the wedge members will more, to envide anarrangement whereby heating of the fuse due to ineffectual electricalconnectionv of the fuse link or the development of loosencss in suchconnection. will be overcome. in this connection it is to be observed,as particularly shown in Figure 1 of the drawings. that the corners ofthe shoulders 13 of the ferrules, at the junction of the contactsurfaces 15 and 16. are rounded in order toprevent cutting of theterminals of the f use link when the wedge members are adjusted inwardlytherebetween. The ribbon 17 of the fuse link will, of course. burn atthe web 18 therein anil this web is provided in order that a minimumamount of gas may be given oll' within the barrel 10. However. it willbe noted that any gas so given off within the barrel may flow throughthe slots 14. it being observed by particularref crence' to Figure-2 ofthe drawings, that the wedge blocks are somewhat shorter than saidslots. From theslots 14 the gases will then flow around. the. headplates 21 of the wedge members to the grooves 24 and thence out throughthe passages 25. Esca )e of the gases'will tbusbe freely permitted.

In Figure 5 of the drawings we have illustrated a somewhat modified formof fuse link. In this modification a fuse ribb'on 27 is employed. Thisribbon is providd intermediate of its ends with a reduced web 28 as inthe preferred construction. Soldered or otherwise connected to the endsof the ribbon are preferably copper terminals 29 and 30. The terminal 29'is provided with a lateral lug 31 while the terminal 30 is straight.Consequently. this terminal may be inserted through the slots 14 of theferrules ll of the'fnse to engage the lug 31 with one of the shoulders13 of one of said ferrules when the terminal I-ltl may then bebcnt'over, asshown in dotted lines, to form a lug engaging one of theshoulders of the otbcr of said ferrules.

In Figure 6 of the drawings we have shown a further modified form offuse link. In this modification. a fuse ribbon 32 is employed. Thisribbon is provided intermediate of its ends with a reduced web 33. as inthe prior modification. Soldered or otherwise secured to opposite endsof the ribbon are preferably copper terminals 34 and 35 respectively.The terminal 34 is formed with oppositely offset arms 36 at the outerends of which are formed oppositely directed lateral lugs 37. Theterminal is formed with oppositely offset, arms 38 similar to the arms36 but these arms 38 are straight. Consequently, the link may, as willbe readily understood in View of the preceding description. be readilyinserted through the barrel of the fuse when'the arms 38 may then bebent over to form lugs similar to the lugs 37 of the arms 36. Byoppositely offsetting the aims 36 and 38, these arms will be adapted toengage the contact surfaces 15 of the slots 1-l of the ferrules;

In Figures 7. 8 and 9 of the drawings, we have illustrated asomewhat'modified form of fuse. this fuse being of the knife blade type.Referringnow'more particularly to these figures, a barrel or receptacle39 is employed. this barrel being similar to the barrel 10 of thepreferred construction. Threaded upon the ends of the barrel areferrules 40 held against accidental displacement by pins 41'. Theferrules 40are identical with the ferrules 11 of the preferredconstruction with the exception that the ferrules 40 are externallythreaded at their outer extremities. Formed within the ferrules areshoulders 42 defining slots 43, the side walls of which provide contactsurfaces 44, while the outer faces of the shoulders provide contactsurfaces 45. Removably fitted through the barrel is a fuse linkpreferabl of the type shown in detail in Figure 10 o the drawings. Thislink includes a fuse ribbon 46 provided intermediate of its ends with areduced web 47. The end portions of the ribbon are coated in anyapproved manner with copper to provide terminals 48 and, as shown in Fiure 7 of the drawings, one of these termina s is engaged with thecontact surfaces 44 and of one of the shoulders of one of the ferruleswhile the other terminal is engaged with corresponding contact surfacesof one of the shoulders of the other ferrule.

Removably fitted within the outer ends of the ferrules are wedge membershaying heads 49 which, while fitting snugly within the ferrules may.nevertheless, be slidably moved therein. pou their inner sides theseheads are pmvided with diametric wedge blocks 50 fitting within theslots 43 of the ferrules and extending from the outer sides of saidheads are blades 51. These blades are preferably resilient andsufliciently flexible to make a good contact. Removably threaded overthe outer extremities of the ferrules are followers in the form ofclamping rings or collars 52 provided with flanges 53'engaging over theouter ends of the heads 49. The collars are provided with 45 of theferrules.

openings or notches A for receiving a spanner wrench or other suitabletool and as willnow be clear, said collars may be adjusted upon theferrules for shifting the wedge blocks 50 into the slots 4?. and forfastening the members in place. These blocks will accordingly tightlybind the terminals 48 of the fuse link in contact with the adjacentcontact surfaces 4- of the ferrules while the heads will be moved toengage the lugs formed from the ends of the terminals 48 for clampingthese lugs in engagement with the adjacent contact surfaces irmelectrical connection will thus be established and maintained betweenthe link and the ferrules. Gases created within the barrel 39 when theweb 47=of the ribbon fuses, will flow through the slots 43 and aroundthe heads 49 to emerge at the outer ends of the ferrules. Such gaseswill accordingly encounter the flanges 53 of the collars 52 to bedirected by said flanges inwardly toward the blades 51 to prevent damageto equipment.

Having thus described the invention, what is.claimed as new is:

1. A fuse comprising a barrel, a ferrule fixed on each end of the barreland each having an internal flat-sided slot, a fuse link extending throu'h the barrel and having bendable terminzils each projectin into theslot in the adjacent ferrule, flat-si ed wedge members each having ablock standing in a slot alongside a terminal and a head standing withinthe outer end of the ferrule and bearing against the extremity of aterminal, and a member screwed to said outer end and contacting withsaid head for urging the wedge member inward.

- 2. In a fuse, the combination of a barrel, a ferrule fast on each endthereof and each having internal shoulders defining a transverse slotand having the outer end of its body threaded, and a fuse link standingwithin said barrel and having its terminals each passing through a slotand bent down onto the outer face of a shoulder in the adjacent ferrule,a wedge member at eachend of the barrel comprising a head within theouter portion of the ferrule to coact with the outer face of theshoulder and a block projecting from the head into the slot along sidethe terminal therein, and an element engaging with the threads at theouter end of the ferrule and contactin with-said head to urge the wedgemember inward.

In testimony whereof we affix our signa- TBS.

WALTER 0. SMITH. [1,. 5. JOSEPH E. GRENACHE. 1.8.

